CN108333565B

CN108333565B - Pulse radar magnetron preheating dynamic delay method

Info

Publication number: CN108333565B
Application number: CN201810142042.7A
Authority: CN
Inventors: 褚人乾
Original assignee: Shanghai Yonzoe Electronic Technology Co ltd
Current assignee: Shanghai Yonzoe Electronic Technology Co ltd
Priority date: 2018-02-11
Filing date: 2018-02-11
Publication date: 2021-12-24
Anticipated expiration: 2038-02-11
Also published as: CN108333565A

Abstract

The invention discloses a pulse radar magnetron preheating dynamic delay method, which utilizes a residual voltage value of a capacitor in a pulse radar magnetron preheating dynamic delay circuit when a pulse radar is started to determine the shutdown time of the pulse radar, and determines the preheating time of the magnetron according to the shutdown time of the radar. The invention also discloses a pulse radar magnetron preheating dynamic delay circuit. The invention utilizes the characteristic of charging and discharging of a capacitor to measure and sense the shutdown time of the radar, thereby realizing dynamic magnetron delay control; meanwhile, a clock circuit needing a battery is not adopted to measure the shutdown time, so that the inconvenience brought to logistics such as air transportation by the battery is avoided.

Description

Pulse radar magnetron preheating dynamic delay method

Technical Field

The invention relates to the technical field of pulse radar magnetron control, in particular to a pulse radar magnetron preheating dynamic delay method and a preheating dynamic delay circuit.

Background

Due to outstanding cost performance and maturity, the pulse radar is widely used in civil navigation radars and is the current mainstream radar system. The pulse radar uses a pulse magnetron with low cost, small size, moderate power and high efficiency to generate a microwave signal with medium power (10kW magnitude) to radiate to the space, and the radar uses part of echoes reflected to a receiving antenna to sense the surrounding environment.

The magnetron mainly comprises five parts, namely an anode, a cathode, an energy output device, a magnetic circuit system and a resonant device (a resonant cavity). The cathode is the heart of the magnetron, and forms a high-frequency electromagnetic field with the anode to emit high-energy electrons, so that the performance and the service life of the magnetron are determined to a certain extent.

After the radar is started (cold start), a magnetron needs to be preheated for a certain time before the radar is switched from standby to emission (hot start), the current method is to preheat a magnetron for a period of time by applying voltage to a cathode filament of the magnetron, and then apply high-voltage modulation pulse, which is important for the normal work and the service life of the magnetron, and the preheating time of the cold start is generally about 3 minutes.

At present, the preheating time of the magnetron is generally set by a radar system through a hardware delay circuit or a software system at regular time, and the starting delay time is fixed, which sometimes causes great inconvenience for an operator. For example, the system is abnormally restarted, the switch is touched by mistake, and the software is restarted, under the condition, the conditions of the magnetron cathode filament and the complete cold start are different, the residual temperature is remained, and the preheating time can be completely shortened.

Disclosure of Invention

One of the technical problems to be solved by the present invention is to provide a dynamic delay method for preheating a pulse radar magnetron, which aims at the disadvantages that the preheating time of the existing magnetron is usually set by a radar system through a hardware delay circuit or a software system at regular time, and the starting delay time is fixed, so that an operator feels very inconvenient sometimes.

The second technical problem to be solved by the present invention is to provide a pulse radar magnetron preheating dynamic delay circuit for implementing the pulse radar magnetron preheating dynamic delay method.

In the method for dynamically delaying the preheating of the pulse radar magnetron according to the first aspect of the present invention, the shutdown time of the pulse radar is determined by using the residual voltage value of the capacitor in the dynamic delay circuit for preheating the pulse radar magnetron when the pulse radar is started, and the preheating time of the magnetron is determined according to the shutdown time of the radar.

In a preferred embodiment of the present invention, the pulsed radar magnetron preheat dynamic delay strategy is as follows:

the pulse radar magnetron preheating dynamic delay circuit comprises a charge-discharge circuit, an ADC (analog-to-digital converter), a main processor, a high-voltage modulation pulser and a magnetron, wherein the charge-discharge circuit comprises a direct-current power supply VCC, a diode D1, resistors R1, R2 and a capacitor C1, the direct-current power supply VCC is controlled by a pulse radar switch, the anode of the direct-current power supply VCC is connected with the anode of the diode D1, the cathode of the direct-current power supply VCC is grounded, the cathode of the diode D1 is connected with one end of a resistor R1, the other end of the resistor R1 is connected with one end of the capacitor C1, one end of the resistor R2 and the input end of the ADC analog-to-digital converter, and the other end of the capacitor C1 is grounded with the other end of the resistor R2; the output end of the ADC is connected with the input end of the main processor, the control end of the main processor drives a switch to be turned on and off, and the high-voltage modulation pulser and the magnetron are respectively connected to two ends of the switch.

By adopting the technical scheme, the invention utilizes the characteristic of charging and discharging of a capacitor to measure and sense the shutdown time of the radar, thereby realizing dynamic magnetron delay control; meanwhile, a clock circuit needing a battery is not adopted to measure the shutdown time, so that the inconvenience brought to logistics such as air transportation by the battery is avoided.

Drawings

FIG. 1 is an electrical schematic diagram of a pulsed radar magnetron preheat dynamic delay circuit of the present invention.

Fig. 2 is a schematic diagram of a charging curve of a charging and discharging circuit in the dynamic delay circuit for preheating the pulse radar magnetron according to the present invention.

Fig. 3 is a schematic diagram of a discharge curve of a charge-discharge circuit in the dynamic delay circuit for preheating the pulse radar magnetron according to the present invention.

Detailed Description

Referring to fig. 1, the pulse radar magnetron preheating dynamic delay circuit includes a charge and discharge circuit, an ADC analog-to-digital converter 100, a main processor MCU200, a high voltage modulation pulser 300, and a magnetron 400. The charging and discharging circuit comprises a direct current power supply VCC, a diode D1, resistors R1, R2 and a capacitor C1, wherein the direct current power supply VCC is controlled by a pulse radar switch, the anode of the direct current power supply VCC is connected with the anode of the diode D1, the cathode of the direct current power supply VCC is grounded, the cathode of the diode D1 is connected with one end of a resistor R1, the other end of the resistor R1 is connected with one end of the capacitor C1, one end of the resistor R2 and the input end of the ADC analog-to-digital converter 100, and the other end of the capacitor C1 and the other end of the resistor R2 are grounded; the output end of the ADC 100 is connected to the input end of the main processor MCU200, the control end of the main processor MCU200 drives a switch K to be turned on and off, and the high voltage pulse modulator 300 and the magnetron 400 are connected to two ends of the switch K, respectively.

The magnetron preheating dynamic delay circuit of the invention has the following control process:

when the radar is started, VCC supplies power to the delay circuit, and D1, R1 and C1 form a charging circuit for starting and electrifying; when the radar is turned off, VCC disappears, D1 is turned off, and C1 and R2 form a discharge circuit. Therefore, when the radar is powered on, the residual voltage value on the C1 actually reflects the power-off time of the radar, and the accurate power-off time of the radar can be measured by the charging and discharging curves of R1, R2 and C1. The residual voltage value at the C1 end is converted into a digital signal through the digital-to-analog conversion ADC, the time for shutdown is measured by the main processor MCU, so that the preheating time of the magnetron is determined, the modulation switch is controlled, high-voltage modulation pulses are loaded on the magnetron, the dynamic and sufficient preheating time of a magnetron cathode filament is ensured, the cold start time is accelerated according to the actual situation, and the waiting time for the radar to enter a transmittable state is shortened.

The dynamic delay strategy of the main processor MCU is as follows:

from the table, it can be known that the parameters of the charge and discharge circuit must ensure that the circuit can identify the maximum shutdown time of 60s after startup, that is, the discharge time of the capacitor must be ensured to be greater than 60s, and the design is performed according to the discharge time of 120s in practice, so that the reliability of the operation is ensured. The charging and discharging time of the capacitor is determined by the capacitance value and the resistance value connected in series, namely the so-called time is constant, and the expression is tau-RC;

in conjunction with the above illustration, assuming that the residual voltage of the capacitor C1, i.e., the initial voltage is V0, the charging voltage is VCC, and assuming that the voltage value of D1 is VD, U is VCC-VD, the capacitor C1 is charged by R1, and the time constant is τ 1 is R1C1, the capacitor charging curve expression is:

Vt＝V0+(U-V0)*[1-exp(-t/τ1)]；

the charging curve is schematically shown in fig. 2.

With a delay of t 5 τ 1, the charge can reach 99% of the maximum. In practice, R1 is small to speed up charging.

Assuming that the capacitor C1 is turned off from the value U, the capacitor is discharged through R2, and the time constant is τ 2 — R2C1, the capacitance charging curve expression is:

Vt＝V*[exp(-t/τ2)]；

the discharge curve is schematically shown in fig. 3.

The discharge is also substantially completed with a delay of t ═ 5 τ 2.

Since the measurement of the radar off time is mainly concerned, an important parameter is τ 2, and since it is considered that 2 τ 2 is mainly discharged (about 86% is discharged) and it is difficult to detect it later, R2 and C1 are determined by setting 2 τ 2 to 120s and τ 2 to 60 s.

And restarting the radar after the radar is shut down, firstly, collecting a voltage value of C1 through a digital circuit, determining the discharge time according to the residual voltage value according to the delay strategy of the table, determining the time needing to be delayed, starting a delay function of timing software by the MCU, and allowing the high-voltage modulation pulse to act on the magnetron after delaying the corresponding time.

Through actual measurement and calibration, this scheme is practical convenient, can compromise the dynamic settlement of pulse radar magnetron preheating time well, to the shutdown back start of short time, need not be according to fixed long-time such as 180 time delays for get into the transmitting state, improved the usability of radar well.

Claims

1. A pulse radar magnetron preheating dynamic delay method is characterized in that a residual voltage value of a capacitor in a pulse radar magnetron preheating dynamic delay circuit when a pulse radar is started is utilized to determine the shutdown time of the pulse radar, and the preheating time of the magnetron is determined according to the shutdown time of the radar;

the pulse radar magnetron preheating dynamic delay strategy is as follows:

measured off time Preheating time of magnetron ≤15s 15s ≤30s 30s ≤45s 60s ≤60s 90s ＞60s 180s

。